Intravascular guide wire and method for manufacture thereof

ABSTRACT

A guide wire, and a method for the manufacture thereof, having a core and a plastic jacket enclosing at least a portion of the core. In some embodiments, the guidewire also includes a radiopaque coil disposed about a first portion of the core wire. The polymer jacket includes a first portion disposed about the radiopaque coil, and a second portion adjacent the first portion and overlaying and in contact with a second portion of the core wire. In some embodiments, the plastic jacket comprises a proximal portion formed of a first plastic material and a distal jacket portion formed of a second plastic material.

This is a continuation of U.S. patent application Ser. No. 08/881,586,filed Jun. 24, 1997; which is a continuation of U.S. patent applicationSer. No. 08/534,113, filed Sep. 26, 1995, now abandoned; which is acontinuation of U.S. patent application Ser. No. 08/319,772, filed Oct.7, 1994, now U.S. Pat. No. 5,452,726; which is a continuation of Ser.No. 08/034,174, filed Mar. 12, 1993, now abandoned; which is acontinuation of U.S. patent application Ser. No. 07/716,678, filed Jun.18, 1991, now abandoned.

Some of the characteristics preferred in guide wires by some physiciansinclude strength, the ability to provide a track for a balloon or otherdevice to advance over, and good torsional transmittance. A discussionof these and other preferred characteristics of guide wires is inEndovascular Surgery, by Moore, W. S. and Ahn, S. S; p. 157, W.B.Saunders Co. (1989). One of the characteristics considered desirable bysome physicians in a guide wire is that it should be easy to grip anduse manually at the proximal portion.

Accordingly, it is an object of the present invention to provide a guidewire with favorable characteristics.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a guidewire, and a method for the manufacture thereof, having a core and aplastic jacket enclosing the core. The plastic jacket comprises aproximal portion formed of a first plastic material and a distal jacketportion formed of a second plastic material. The distal end of theproximal jacket portion and the proximal end of the distal jacketportion are of substantially equal outer diameters so as to form asmooth transition between the proximal and the distal jacket portions.

According to another aspect of the invention, there is provided a guidewire, and a method for the manufacture thereof, with a core that isselectively formable in at least a distal portion thereof, and a plasticjacket encasing the selectively formable core. The plastic jacket has adistal portion with a hydrophilic coating and a proximal portion withouta hydrophilic coating.

According to another aspect of the invention, there is provided a guidewire, and a method for the manufacture thereof, having a core that isselectively formable, at least in a distal portion thereof, and aplastic jacket encasing the core. The plastic jacket has a distalportion that is more radiopaque than a proximal portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a first embodiment of the presentinvention.

FIG. 2 a shows a cross section of the embodiment of FIG. 1 along line 2a-2 a′.

FIG. 2 b shows a cross section of the embodiment of FIG. 1 along line 2b-2 b′.

FIG. 2 c shows a cross section of the embodiment of FIG. 1 along line 2c-2 c′.

FIG. 3 is a sectional view of another embodiment of the presentinvention.

FIG. 4 a sectional view of yet another embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

Referring to FIG. 1 there is depicted a first preferred embodiment ofthe present invention. This embodiment is an intravascular guide wire10. This guide wire 10 has a distal end 12 and a proximal end 14. Theguide wire 10 may be approximately 180 centimeters in length and have anoutside diameter of approximately 0.035 inches. Other lengths anddiameters may be provided so that a range of sizes of guide wires may beavailable suitable for the different needs of various individualpatients and the preferences of physicians. Such other sizes arecontemplated within the scope of the present invention and of thisembodiment in particular.

The guide wire 10 includes a core 18. The core may be made of a strong,yet flexible material, such as a metal, like stainless steel or nitinol,or other materials, or combinations thereof. In a preferred embodiment,the core 18 is made at least in part of a selectively formable metallicmaterial, as explained in more detail below. The core 18 extends fromthe distal end 12 to the proximal end 14 of the guide wire 10.

In a preferred embodiment, the core 18 includes a distal portion 20 anda proximal portion 22. The proximal and distal portions are preferablyformed of a single metallic wire. The distal portion 20 has a smallercross section than the proximal portion 22 to impart greater flexibilityto the distal end of the guide wire. In a preferred embodiment, thedistal portion 20 of the guide wire comprises a series of stages orregions of tapered portions and portions of uniform cross section, asexplained in more detail below. The series of stages of tapered portionsand portions of uniform cross section are intended to impart increasinglevels of flexibility to the guide wire toward the distal end.

In this embodiment, the proximal portion 22 of the core 18 has adiameter of approximately 0.018 inches. FIG. 2 a shows a cross sectionof the guide wire in the proximal portion 22. The proximal portion 22 ofthe core 18 extends from a proximal end of the guide wire 10 to aproximal end of the distal portion 20 of the core 18. In thisembodiment, the distal portion 20 of the core 18 is approximately 10.50inches in length.

The distal portion 20 of the core includes a first region 24 immediatelyadjacent to and distal of the proximal portion 22. This first region 24of the distal portion 20 of the core is approximately 2.0 inches inlength. In the first region 24, the core 18 tapers from the diameter ofthe proximal portion 20 (e.g. 0.018 inches) to a diameter ofapproximately 0.009 inches. In this first region 24, the core has acircular cross section.

The distal portion 20 of the core next includes a second region 28immediately adjacent to and distal of the first region 24. This secondregion 28 of the distal portion 20 of the core is approximately 4.0inches in length. FIG. 2 b shows a cross section of the guide wire inthis region. The second region 28 is a region of approximately uniformcross section. In this second region 28, the core also preferably has acircular cross section.

The distal portion 20 of the core next includes a third region 30immediately adjacent to and distal of the second region 28. This thirdregion 30 of the distal portion 20 of the core is approximately 2.0inches in length. In the third region 30, the core 18 tapers from thediameter of the second region 28 (e.g. 0.0090 inches) to a diameter ofapproximately 0.00525 inches. In this third region 30, the core also hasa circular cross section.

The distal portion 20 of the core next includes a fourth region 32immediately adjacent to and distal of the third region 30. This fourthregion 32 of the distal portion 20 of the core is approximately 1.75inches in length. In the fourth region 32, the core 18 is flattenedtoward a distal end 34 thereof to form a ribbon shape having dimensionsof approximately 0.010 by 0.00225 inches. FIG. 2 c shows a cross sectionof the guide wire in this region. The ribbon shape of this region causesthe guide wire to tend to flex in one plane thereby facilitating the usethereof. In the fourth region 32, the length of the distal flattenedportion is approximately 0.5 inches, the length of the portion ofcircular cross section is approximately 0.7 inches, and a transitionzone between these portions has a length of approximately 0.7 inches.

The distal portion 20 of the core wire, including the various regions oftapered and uniform cross section, may be formed by methods known in theart, such as chemical washes, polishes, grinding, or compressing.

The guide wire 10 also includes a plastic jacket 38 extending from theproximal end 14 to the distal end 12. In a first preferred embodiment,the plastic jacket 38 is formed of a proximal jacket portion 40 and adistal jacket portion 42. The outside diameter of the plastic jacket 38in this embodiment is approximately 0.035 inches although otherdiameters may be provided for guide wires of other dimensions.

The distal jacket portion 42 is approximately 18 inches in length andextends proximally from the distal end of the guide wire 10. The distalend of the distal jacket portion 42 extends over and covers the distalend of the core wire 18. The proximal jacket portion 40 extends from theproximal end of the guide wire 10 distally. In this embodiment, theproximal end of the distal jacket portion 42 substantially abuts thedistal end of the proximal jacket portion 40. At the location at whichthe proximal and distal jacket portions abut, the outside diameters ofthe jacket portions are substantially the same and form a smoothtransition at that location so that the guide wire can be readilyinserted into and moved within a catheter or vessel or that a catheteror other device can be readily advanced over the guide wire.

These two jacket portions are provided to yield features related tofunctions specifically associated with their respective locations. Inthis embodiment, the proximal jacket portion 40 is made of a Teflon®material and the distal jacket portion 42 is made of polyurethane.Alternatively, the proximal jacket portion 40 may be made of anothermaterial or combination of materials, such as flouroresins, such asKynar (CH₂CF₂), high density polyethylene, Delrin (polyacetal), Hytrelor polypropylene. The distal jacket portion 42 may be made of otherpolymers or co-polymers, or elastomers, or fluoroelastomers or silicone,Hytrel or nylon.

In a preferred embodiment, the distal jacket portion has a hydrophiliccoating applied to it to make the surface highly lubricious when itcomes in contact with a fluid such as blood. The hydrophilic coating isbelieved to improve the biocompatability of the guide wire. This isbased in part on observations that hydrophilic surfaces are generallyless thrombogenic, and more specifically, tend to exhibit reducedplatelet activation and aggregation compared to hydrophobic surfaces. Ina preferred embodiment, the composition of the coating is a mixture of ahydrogel and a polyurethane in an organic/water solvent mixture. Thesolution mixture is applied to the distal jacket portion 42 and dried.In a preferred embodiment, polyvinyl pyrrolidone (PVP) is used as thehydrogel and commercial polyurethanes such as Dow (Pellethane 2363Series) or Thermedics (the Tecophane or Tecoflex families) may be used.A polymer blend having an affinity to the polyurethane substrate of thedistal jacket portion (via the urethane and the solution) is used whilethe other component is a slippery otherwise water-soluble material. Thehydrogel will not tend to dissolve away because it is ensnared with thewater insoluble polyurethane.

As an alternative to using a hydrophilic coating, a different coatingmay be applied to the guide wire jacket to enhance its lubriciousness.Such a coating may be a silicone coating or other lubricious material.

In a preferred embodiment, the hydrophilic coating is applied only to adistal portion of the guide wire, and in particular, only to the distaljacket portion 42. This is facilitated because the preferred hydrophiliccoating is formulated to adhere to the urethane material of the distaljacket portion but not adhere to many different materials including thepreferred material of the proximal jacket.

As mentioned above, the proximal jacket portion is made of Teflon whichalso provides a low friction surface though not as low friction as thatof the distal jacket portion with the hydrophilic coating applied. It isadvantageous for the proximal portion of the guide wire have a lowfriction surface in order to traverse a catheter lumen or a vessel.However, because the proximal portion of the guide wire will likely bein a portion of the vasculature not as tortuous as the distal portion,it would not require a surface of as high lubricity as the distalportion and therefore Teflon is a good choice of materials.

Moreover, this combination of low friction surfaces has the additionaladvantage that a very low friction surface, such as one having ahydrophilic coating, is used only on the distal portion of the guidewire. A very low friction surface, such as one having a hydrophiliccoating, would be so slippery that it would be difficult for a physicianto handle if it were on the proximal end as well. Accordingly, at theproximal end of the guide wire, this embodiment includes a surface thatis easy for the physician who would be manipulating the guide wire fromthe proximal end to handle and yet is of sufficiently low friction sothat it can readily traverse portions of the patient's vessels andprovide good guide wire movement in a catheter.

It is also preferred that the distal portion of the guide wire beprovided with enhanced radiopaque properties. In the preferredembodiment, this is done by loading the material from which the distaljacket 42 is made with radiopaque materials such as barium, bismuth ortungsten. The loading of the distal jacket of polyurethane with aradiopaque material enhances the ability of a physician to observe theposition of the distal end of the guide wire in the body of the patientby means of fluoroscopy.

In a preferred embodiment, the proximal jacket portion 40 of Teflon isheat shrunk onto the core wire. The distal jacket portion 42 isinstalled over the core wire by heating a sleeve of polyurethane to atemperature until it is reformed around the core wire. The proximal anddistal jackets may be finished by a centerless grinding method so thatthe transition between the jacket portions is smooth.

In a further embodiment, the guide wire has a core that is selectivelyformable at least in a distal portion thereof. By a selectively formablecore, it is meant that the wire from which the core is made may be bentto a particular shape and that the shape will be maintained by the wire.This allows the physician to impart a particular shape to the guidewire, by bending or kinking it for example, to facilitate its placementinto a patient's vasculature. To provide this selective formability, ina preferred embodiment, the entire core wire may be made of stainlesssteel. Other materials may be used to provide this feature. The use of aformable material, such as stainless steel, provides advantages in theguide wire over materials that cannot be formed, such as superelasticmaterials like nitinol. Superelastic materials, like nitinol, are soresilient that they tend to spring back to their original shape even ifbent, thus are not formable. Although superelastic material may beprovided with a “preformed” memory shape, such a preformed shape istypically determined in the manufacture of the guide wire and cannotreadily be altered or modified by the physician by simply bending theguide wire prior to use. Although use of superelastic materials such asnitinol in guide wire applications may provide some advantages incertain uses, a formable core, such as of stainless steel, which can beformed by the physician to a shape suitable for a particular patient orpreferred by that physician, provides an advantage that cannot beobtained with a superelastic core guide wire.

In a further preferred embodiment, the guide wire may include a corewire of a material having formable properties at a distal portionthereof and non-formable (e.g. superelastic properties) proximally. Sucha construction would provide advantages in certain guide wire usages. Aguide wire having these properties could be formed by using asuperelastic material such as nitinol for the core wire and reducing itssuperelasticity in a distal portion thereof. This may be effected byheating the distal end of the superelastic core wire. Another means toreduce the superelastic properties of a distal end of the core wirewould be to shape it mechanically, e.g. flattening it. Other methods ofreducing the superelastic properties of the core wire may also be used.With a core wire having this dual combination of a formable distalportion and a superelastic proximal portion, desired shapes could beimparted by a physician to the distal end of the guide wire tofacilitate making turns, etc., in tortuous vessel passages, while in thesame guide wire the more proximal portion would possess superelasticproperties to allow it to follow the distal portion through the tortuouspassages without permanently deforming. This combination of formable andnon-formable properties in the core wire may also be provided by usingmore than one material for the core wire or more than one wire.

FIG. 3 shows another preferred embodiment of the present invention. Thisembodiment of the guide wire is similar in some respects to theembodiment of the guide wire, described above. Although this embodimentof the guide wire may be provided in large sizes (e.g. 0.035 inches),this embodiment is especially suitable for a guide wire of a smallerdiameter, e.g. having an outer diameter of approximately 0.018 inches.If provided in a guide wire of smaller diameter, the diameter of thecore wire and plastic jacket would be correspondingly smaller. Like theembodiment described above, this guide wire includes a core 52surrounded by a plastic jacket 54. The core 52 is preferably of aselectively formable material, as described above. In addition, in thisembodiment, a marker 56 is provided at a distal end 58 of the guide wire50. This marker 56 is located around the distal portion of the core wire52 underneath the plastic jacket 54. In this embodiment, the marker 56is a coil spring. Alternatively, the marker may be a ribbon, anotherwire, or any other similar component. A tip 60 may be provided at thedistal end of the core wire 52 to facilitate placement and connection ofthe marker 56.

The marker 56 may be made of platinum or stainless steel or othermaterial. The marker 56 may be provided with radiopaque properties byselecting a material such as platinum. This may be in addition or as analternative to providing radiopaque properties in the jacket portionthrough the use of loading with radiopaque materials. The use of aradiopaque marker may be preferred in smaller diameter guide wires wherethe plastic jacket, even if loaded with a radiopaque material, is ofsuch a small size that it could be difficult to discern underfluoroscopy.

FIG. 4 shows another preferred embodiment of the present invention. Inthe embodiment in FIG. 4, a core wire 20 extends from a distal to aproximal end of the guide wire. As in the embodiment described above,the core wire 20 is surrounded by a core wire jacket 38. In thisembodiment, the core wire jacket 38 is comprised of a first jacket 70.The first jacket 70 of this embodiment is comprised of a first portion72 and a second portion 74. The core wire jacket 38 also includes asecond jacket 76. The second jacket 76 covers the first jacket 70 overthe second portion 74 thereof. The second jacket 76 may correspond tothe proximal jacket of the previous embodiments. The second jacket 76may be a thin tubing that is heat shrunk onto the first jacket 70 over aproximal portion thereof. Alternatively, the second jacket 76 may beapplied by other methods, such as by spraying, dipping, etc.

In a preferred embodiment, the outer diameter of the second jacket 76when it is in position surrounding the first jacket 70 is approximatelythe same as the outer diameter of the first jacket 70 in the firstportion 72 thereof at least in an area 80 of the guide wire where thesecond jacket 76 ends so that the overall diameter of the guide wirethrough this area 80 is substantially uniform. This uniformity may befurther enhanced by polishing, grinding, or other means. To furtherprovide for this uniformity in diameter, the second portion 74 of thefirst jacket 70 may be provided with a diameter that is less than thatof the first portion 72 of the first jacket 70. This reduction indiameter may be formed by grinding, stretching, chemical erosion, orother means.

In a preferred embodiment, the second jacket 76 covers the proximalportion of the guide wire and an exposed first portion 72 of the firstjacket 70 extends to a distal end of the guide wire. The first jacket 70and second jacket 76 may be provided with properties specificallydirected to their respective functions, as explained above in regard tothe embodiment of the guide wire in which the jackets are in an abuttingrelationship. For example, the first jacket 70 may be made ofpolyurethane and the second jacket 76 may be made of a Teflon-likematerial. A hydrophilic coating may be applied to the first jacket 70 inthe first portion 72 thereof to enhance lubricity, as explained above.If this embodiment of the guide wire is intended for use in peripheralregions of the body, it may have an outside diameter of approximately0.035 inches. Other dimensions may be suitable as well for other sizeguide wires. As in the previously described embodiments, the core 20 maybe a material such as stainless steel or nitinol and may have formableproperties in at least a portion thereof.

It is intended that the foregoing detailed description be regarded asillustrated rather than limiting and that it is understood that thefollowing claims including all equivalents are intended to define thescope of the invention.

1. A guide wire comprising: an elongated core having a proximal regionand a distal region, the distal region of the core having a proximalportion and a distal portion; a radiopaque coil disposed about thedistal portion of the distal region of the core; a plastic jacketdisposed about the distal region of the core and the radiopapue coil,the plastic jacket being in intimate contact with the proximal portionof the distal region of the core alone a length thereof; and wherein adistal end of the radiopaque coil is connected to a distal end of thecore to form a connection, and wherein the plastic jacket encapsulatesthe connection.
 2. A guidewire as in claim 1, wherein the distal portionof the core has a relatively flat cross-sectional shape.
 3. A guidewireas in claim 2, wherein the proximal of the core has a relatively roundcross-sectional shape.
 4. A guide wire comprising: an elongated corehaving a proximal region and a distal region, the distal region of thecore having a proximal portion and a distal portion, the distal portionof the distal region having a relatively flat cross-sectional shape andthe proximal portion of the distal region of the core having arelatively round cross-sectional shape; a radiopaque coil disposed aboutthe distal portion of the distal region of the core, with a distal endof the radiopaque coil connected to a distal end of the core to form ajunction; and a plastic jacket having a smooth outer surface disposedabout the proximal portion of the distal region of the core, theradiopaque coil, and the junction, the plastic jacket being in intimatecontact with the radiopaque coil and the proximal portion of the distalregion of the core.
 5. A guide wire comprising: an elongated core wireincluding a first portion and a second portion disposed adjacent thefirst portion; a radiopaque coil disposed about the first portion of thecore wire; a polymer jacket including a first section disposed about theradiopaque coil, and a second section adjacent the first section andoverlaying and in contact with the second portion of the core wire.
 6. Aguide wire comprising: an elongated body assembly including a firstportion and a second portion disposed adjacent the first portion, thebody assembly including an elongated core wire extending through boththe first and second portions; the first portion including a radiopaquecoil disposed about the core wire, and a first section of a polymerjacket disposed about the radiopaque coil; the second portion includinga second section of the polymer jacket overlaying and in contact withthe core wire.